The interviewer reviewed my entire resume. Direct questions about my work history, reasons for leaving, roles and responsibilities. One thing I gathered: A) They are very interested in reasons for leaving, as they should be, however I get the feeling that someone with an extensive work history at more than a few firms will be more heavily scrutinized than someone at one firm for a long time. More professionals these days switch jobs every few years in order to advance their career, however, I feel the interviewer does not understand this phenomena.

Awful. They are not hiring. This is a ghost position... all of them are. They want someone to take advantage of. They do not want to hire you or pay you your worth. They are just taking the temperature of the market.